Spark-gap apparatus



Aug. 3 1926. 1,594,457

` P. DAVEY SPARK GAP APPARATUS Filed August 28, .1922

Patented Aug. 3, 1926.

UNITED STATES 1 ETE1aI DAvEY, OE LONDON, ENGLAND, AssIGNOn TO HERBERT KENNEDY a CONEANY PATENT OFFICE.

SPARK- GAE APPARATUS.

Application nl ed August 28, 1922, Serial No.

sp ark gap apsuch apparatus, so arrange-d or 'adjusted as to permit the passage of the irstdischarge, but too wide to'be` bridged by ,the return and subsequent pulsations'from any single discharge.

A further object of theinvention is to.

provide an improved form of portable spark-gap apparatus which maybe com.- bined with a holder for a lamp of the electron discharge type.

A further object is to provide in an ap paratus flashes of light, means whereby'a gap in the circuit (either in series or in parallel) of the discharge apparatus may be adjusted to suit'variations' of speed or other conditions.

Une form of the invention is illustrated4 in the accompanying drawings in which Fig. 1 is a section,

Fig. 2 is a side elevation at a right angle to Fig. 1 with lamp and reflector removed.

Fig. 3 is a plan View of the lamp-holder. The lamp: 1 of the electron discharge type contacts with a master lamp holder of'which the plunger 2 is earthed, and the plunger 3 is connected to one terminal 4 of the'spark gap device.' This. terminal 4 is. in a fixed position within a wire gauze envelope 5 to enable the device to be used if necessary in an explosive atmosphere and a second terminal 6 with a screwed shank 6a is adjustable by means of the milled nutl to vary the gap between the terminals.

The lam'p holder and spark gap apparatus are both carried by ahandle 7 provided with a. hook 8 by whichit may be conveniently hung` in a fixed position When required, and the electrical (oscillatory) supply is introduced, by means of iexible cable 9 carrying two conductors, one of which is 584,732, and lai amt Britain nal-gn 29', 1921.

sweated into a 'sleeve 10 so making contact with theadjustable terminal-:of the Igap and the other (or earthed conductor) is clamped under the head of a set screw 11, so making contact through the metallic arts` of the holder and wire 12 with the 'p unger 2.

In order tO-.putu other electron discharge lamps in circuit'fwith the same spark .gap device a transverse plug opening is made having a. spring 13 in contact with the-fixed spark gap terminal and the groove 7a and ye 7b are formedin the handle tocarry the supplementary lead or leads.

y1. In stroboscopic a paratus the combination of any electron dlscharge lamp, means to supply oscillatory electrical discharges at very short but comparatively' gradually vae `'riable intervals lso as .to produce flashes of light from said lamp, a spark-gap device in series with said lamp,and means to vary the sparlbgap so as torender inoperative to 2. A form of t e apparatus set forth in claim l-including also a portable holder carrying both said lampand said means to vary the yspark-gap, whereby an observer can simultaneously both direct `the lamp upon 'any body or mechanism under study and adjust the spark-gap in 'accordance with the visual sensation receivedfrom the said body or mechanism..

produced in known manner by periodic light 3. Method of defining stroboscopic images flashes from an electron discharge lamp played upon a body under observation, consisting in viewing the body by. the light of said flashes and varying a spark-gap in series with sa'id lamp until a single'c'lear image is obtained.

4. Method of maintaining clear stroboscopic images of bodies moving periodically at varying speeds, said images being produced in known manner by means of light flashes at corresponding periods from anelectron discharge'lamp, consisting` in placing` a spark-gap in series with said lampand varying'said spark-gap in accordance with any indications of varying appearance of the bodyas the speed varies.

In testimony whereof I ailx .my signature.

. PETER DAVEY. 

